No problem, let's work through this together. We're starting with 546426 and are subtracting 72690 from it.

Step 1: We'll start by subtracting the digit 0 and the borrow 0 from 6 in column 1 and get 6.
6 is the first digit of our result.

Step 2: We'll start by subtracting the digit 9 and the borrow 0 from 2 in column 2 and get -7.
We add -7 to 10 and get 3 as the next digit of the result.

Step 3: We'll start by subtracting the digit 6 and the borrow 1 from 4 in column 3 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

Step 4: We'll start by subtracting the digit 2 and the borrow 1 from 6 in column 4 and get 3.
3 is the next digit of our result.

Step 5: We'll start by subtracting the digit 7 and the borrow 0 from 4 in column 5 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

Step 6: We'll start by subtracting the digit 0 and the borrow 1 from 5 in column 6 and get 4.
4 is the next digit of our result.

So, 546426 - 72690 = 473736.